We will study five mechanisms which appear to be possible physiological mediators by which emotional arousal is able to trigger asthmatic symptoms. The five are: 1) Hypocapnia due to emotional hyperventilation; 2) Stimulation of the airways' irritant receptor broncoconstrictor reflex by hyperventilation; 3) The Groen-Dekker maneuver (constricting the trachea and applying excessive exhalational effort); 4) Insufficient epinephrine response to arousal; and 5) An increase in the norepinephrine/epinephrine catecholamine ratio. Volunteer adult asthmatics will try to vividly recall arousing life events while variables to assess each of these five mechanisms are measured to determine which, if any, of the five covaries with arousal induced changes in pulmonary functions. Physiological and catecholamine responses, medical histories, and personality characteristics will be compared among nonasthmatics, asthmatics with, and asthmatics without a pulmonary response to arousal. Asthmatics with the arousal effect will be studied again where we will attempt: First, to block the pulmonary changes in aroused asthmatics by blocking the purported mediator; and Second, to elicit pulmonary changes in relaxed asthmatics by eliciting the purported mediator.